Tensile Behavior of Alternative Reinforcing Materials as Fiber Reinforced Cementitious Mortar FRCM (original) (raw)
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Durability of Fabric-Reinforced Cementitious Matrix (FRCM) Composites: A Review
Applied Sciences
Strengthening and rehabilitation of masonry and concrete structures by means of externally bonded fabric-reinforced cementitious matrix (FRCM) (also referred to as textile reinforced mortar (TRM)) composites was proposed as an alternative to the use of fiber-reinforced polymer (FRP) composites due to their good mechanical properties and compatibility with the substrate. However, quite limited studies are available in the literature regarding the long-term behavior of FRCM composites with respect to different environmental conditions. This paper presents a thorough review of the available researches on the long-term behavior of FRCM composites. Namely, (i) test set-ups employed to study the FRCM durability, (ii) conditioning environments adopted, and (iii) long-term performance of FRCM and its component materials (mortar and fiber textile) subjected to direct tensile and bond tests, are presented and discussed. Based on the available results, some open issues that need to be covered ...
MATEC Web of Conferences, 2018
Vegetable fibers are a hierarchical structure material in the macro, micro and nanometric scales that have been used as reinforcement in cementitious materials. In nanoscale, the nanofibrillated cellulose has the advantage of having good mechanical performance and high specific surface, which contributes to improve the adhesion between fiber and matrix. In hybrid reinforcement, with micro and nanofibers, nanofibrillated cellulose forms bonding with the matrix and acts as stress transfer bridges in the nano-cracking with corresponding strengthening of the cementitious composite. Processing has a strong influence on performance of the fiber cement composite. Two fabrication methods were evaluated: (i) slurry dewatering followed by pressing and (ii) extrusion. The extrusion process strongly depends on the rheological characteristics of the fresh cement material but it can better organize the microstructure of the fiber cement due to the partial orientation of the fibers in the extruder direction. Curing process also plays a key role in the performance of the final product. Accelerated carbonation at early age is a promising technology and a strategy to mitigate the durability problems with the composite materials; it decreases porosity, promotes a higher density in the interface guarantying a good fiber-matrix adhesion and a better mechanical behavior. Alternative MgO-SiO2 clinker free binder is also presented as a suitable alternative to cementitious products reinforced with cellulosic pulps. Finally, mechanical behavior of fiber cement under flexural loading is evaluated by modulus of rupture, fracture toughness, the initial crack growth resistance in cement matrix, and fracture energy that is obtained to evaluate the influence of toughening mechanisms promoted by fibers, such as pullout and bridging, on the mechanical performance of the composites. Degradation during the service life is also crucial for the evaluation of the durability of the resulting materials and components in real applications exposed to different environmental conditions as roofing, partitioning or ceiling elements. It can be concluded that more sustainable and high performance components based on engineered natural raw materials for civil construction can bring valuable contributions for the affordable housing in particular to developing region.
A review on Properties of Fiber Reinforced Cement-based materials
IOSR Journal of Mechanical and Civil Engineering, 2016
Mixing of horsehair and straw with the clay to form floor and bricks was one of the earliest example in which fiber was utilized to strengthen a brittle matrix. Romualdi was first to propose the use of steel fibers as a reinforcement material in his 1963 and 1964 papers. Since then, a plethora of books and papers have been published on the use of various fibers in cement-based material. Published literature shows huge potential of fibers as a reinforcement material. A comprehensive overview of the published literature on the use of fibers in cement-based material is being presented. Effect of fibers on properties of cement-based material such as workability, compressive strength, flexural strength, split tensile strength, shrinkage, impact resistance, fatigue behavior and durability has been presented.
Sustainable fabric-reinforced cementitious composites for the strengthening of masonry elements
The present PhD thesis addresses the development of a sustainable composite system made from natural fabrics and a cementitious matrix for strengthening masonry structures. Woven fabrics of flax and sisal fibres and a lime-based cementitious matrix were used to prepare FRCM composites. An extensive physical and mechanical characterisation of the constituent materials and the resulting composites was conducted at the Laboratory of Testing Materials and Structures of the Department of Civil Engineering at the University of Calabria. The durability of the fibres was considered as the main parameter to evaluate the feasibility of using the cementitious matrices for incorporation into composites reinforced with natural fibres. Composite samples were prepared using one, two or three layers of flax and sisal fabric strips and the cementitious matrix that did not affect the mechanical performance of the fibres aged in the matrix. The composites were subjected to tensile tests to study their...
2019
Due to its low tensile strength and brittle behavior, the use of concrete as structural material has required the use of tensile reinforcement, traditionally on the form of reinforcing bars placed on the locations in which high tensile stresses are expected. In previous decades, the use of steel, glass, or plastic fibers dispersed randomly on the fresh concrete mix for the total or partial replacement of reinforcing bars has shown to provide significant increase on the tensile and flexural strength, abrasion resistance, permeability, toughness and durability of concrete. The use of this composite material, known as fiber reinforced concrete (FRC) or mortar (FRM), for industrial pavement, tunnel linings, and hydraulic and precast structures has shown satisfactory results. More recently, the use of FRC and FRM for the strengthening of existing concrete and masonry structures has caught the attention of researchers worldwide. Unfortunately, experimental evidence on the topic is still s...
Tensile Behavior of High Content Steel and Polypropylene Fibre Reinforced Mortar
In this study, the behaviour of high content of steel and polypropylene fibre reinforced concrete under direct tensile loading using dog-bone shaped specimens was studied. Two different fibres, steel and polypropylene, were used at 5 different volume fractions from 1% to 5%. It was found that the tensile properties of FRC depended mostly on the type and content of fibre. Steel Fibre Reinforced Concrete (SFRC) was found to behave in a single peak manner with peak load occurred at a very small deformation. In the case of Polypropylene Fibre Reinforced Concrete (PFRC), the response was mostly a double peak response with the occurrence of second peak at large deformation. Steel fibre was believed to contribute more on strength while polypropylene fibre was believed to mainly contribute on the post-peak ductility.
2: 4 (2012) 266-271 Alternative Ways of Reinforcing Cement Composites
This paper presents the results of laboratory research on concrete beams with alternative types of reinforcement, assum-ing a constant volume of fibers. As the reinforcement of the cement matrix, two types of macro-fibres, namely steel and poly-propylene fibres, were used. In addition, traditional beam reinforcement in the form of aligned, smooth, and ribbed steel rods were tested. In the case of the long fibers-the steel bars were assumed to force the long fibers to adopt a certain position -four rods at the corners of the cross section, two of which were in the tension zone and two in the compression zone. By introducing a slip sleeve in three stirrups to stabilize the transverse bars in the desired position, efforts were made to ensure the independ-ent operation of each of the four rods. It was shown that the highest load-carrying capacity and the toughness of the compo-site, was obtained for concrete beams reinforced with ribbed steel rods. Unexpectedly, the beams with the polyp...
Mechanical performance and durability of treated palm fiber reinforced mortars
International Journal of Sustainable Built Environment, 2013
The performance of cement mortar reinforced with varying percentages of treated bundled date palm fibers is investigated to appraise their feasibility for structural and non-structural applications. The study first entailed the evaluation of two different alkali pre-treatments at varying concentrations by subjecting treated and untreated bundled fibers to tensile testing. The suitable pre-treatment was then adopted while casting cement mortar mixes. The physical properties of fresh mortar was studied through setting times and, for mortar mixes cured up to 28 days, through parameters such as drying shrinkage and water absorption. The unconfined compressive strengths, split tensile strengths as well as the flexural strengths of the cured mortar mixes at two different ages were undertaken to assess their mechanical properties; while the durability was gauged based on their sulfate resistance for up to a period of four months.
2020
Fabric Reinforced Cementitious Matrix (FRCM) is a relatively new material used for strengthening applications of reinforced concrete structures. Several studies reported in the literature have indicated that the bond between FRCM layers and the concrete substrate is one of the main factors that affect the performance of the system. Few studies have attempted a combined approach of analyzing the surfaces between the three layers of this composite (fibres-matrixconcrete). An investigation of the bond behavior is studied in this thesis with an emphasis on the fibre-matrix and the concrete-matrix interfaces. The efficacy of surface preparation methods and the existing concrete strength were used to evaluate the bond at the concrete-matrix interface. The fibre-mortar width ratio was used to analyze the bond at the fibre-matrix interface. This experiment was completed in two phases: 72 concrete blocks (150x150x165mm) in double shear testing and 12 small concrete beams (150x150x500mm) in flexural testing. For double shear, the varying parameters included 1) surface preparation (untreated, grinding, sandblasting, shotblasting, and combination), 2) fibre-mortar width ratio (1:1 and 1:2) with fibre widths of 120mm and 60mm, and 3) concrete strength (30MPa and 50MPa). The double shear test results indicated that the bond strength increased with enhanced methods of surface preparation. Surface grooving reduced the debonding response, and combined surface preparation methods were effective at eliminating debonding failures. Also, the fibre-mortar ratio of 1:2 exhibited higher bond strength and reduced bond failure than the 1:1 ratio. The concrete strength had an insignificant effect on the bond strength and failure mode. For flexural specimens, the surface preparation method was examined. The surface preparation had a significant effect on the bond strength, and all failures occurred at the fibre-matrix interface. The bond strength was on average 44.5% higher for the flexural than for the double shear specimens. v PREFACE This thesis is based on the original, experimental work completed in whole by the author in the School of Engineering at the Okanagan campus of the University of British Columbia. The author was responsible for completing all aspects of the project including literature review, material acquisition, experimental work, data collection and analysis, and thesis writing. Considerable guidance and supervision throughout the thesis work were contributed by Dr. Ahmad Rteil. Major portions of chapter 3 and 4, and a minor portion of chapter 2, have been submitted to peer-reviewed journals and conferences for publication. The following is a list of publications based on the thesis: